The present invention resides generally in the field of devices and methods useful for the occlusion of vascular vessels, and in a particular aspect relates to the occlusion of the greater or lessor saphenous vein to treat complications, such as varicose vein condition, resultant of venous reflux.
As further background, the human venous system generally includes a superficial venous system and a deep venous system, with perforating veins connecting the two systems. In human legs, the superficial system includes the great saphenous vein and the short saphenous vein. The deep system of the legs includes the anterior and posterior tibial veins which join to form the popliteal vein, which becomes the femoral vein when united with the short saphenous vein.
Such venous systems are designed to carry blood back to the heart. To facilitate this function, the venous systems contain one-way valves, which are typically bicuspid. The failure of venous valves leads to retrograde flow or reflux within the venous system. This can result in various venous diseases which include varicose veins and chronic venous insufficiency. In the varicose vein condition, the superficial veins of the leg become dilated and tortuous and can result in discoloration, pain and ulceration. The varicose vein condition commonly involves the incompetence of one or more venous valves which allow reflux of blood from the deep venous system to the superficial venous system or reflux within the superficial system. In many cases, blood from the deep vein system refluxes back down the greater saphenous vein leading to varicosity within superficial veins below the greater saphenous vein.
Surgical stripping of the greater saphenous vein is an extensively practiced technique for treating the varicose vein condition. In this technique, an incision is made in the groin to expose the sapheno-femoral junction, where the great saphenous vein and its branches are ligated. The distal portion of the greater saphenous vein has been exposed by incision interior to the medial inalleolus, and a stripping device is introduced to exit from the proximal saphenous vein. After holding the leg vertical for a time to empty the venous tree, the vein is stripped from the ankle to the groin. In cases wherein the small saphenous vein is also incompetent, it is stripped at the same time from an incision posterior to the lateral malleolus to the popliteal space. After stripping, the leg is held vertically for a time to permit vessel ends to retract, constrict and clot. The stripping procedure is commonly followed by the removal of collateral veins working through small incisions using an avulsion-extraction technique.
More recently, techniques have been developed to try to avoid the invasive stripping procedure and its associated complications. For example, techniques and devices have been developed to treat the varicose vein condition with radiofrequency (RF) energy. In these techniques a catheter having an electrode tip is used to deliver RF energy within the vein to be treated. The RF energy causes localized heating and shrinkage of the venous tissue. The electrodes can be drawn through or repositioned within the vein to treat different sections or segments of the vein. For additional information on RF treatments and devices, reference can be made for example to U.S. Pat. Nos. 6,200,312, 6,179,832, 6,165,172, 6,152,899, 6,071,277, 6,036,687, 6,033,398, 6,014,589, and 5,609,598.
Another technique which has been developed is the endovenous laser technique. This technique is typically performed under local or regional anesthesia. A bare laser fiber is inserted into the diseased vein and delivers laser light in a pulsed fashion to heat the vein to cause damage and constriction. See, e.g., Gorisch et al., “Heat Induced Contraction of Blood Vessels”, Laser Surgery Medicine 2(1), 1-13(1982). Other techniques for treating the varicose vein condition includes sclerotherapy, in which a sclerosing solution is injected into the vein to damage the interior of the vein, followed by compression wrapping to facilitate permanent closure of the damaged vein. Phlebectomy is a procedure also utilized to treat varicose veins, typically medium sized and larger veins. In this procedure, small stab incisions are made in the skin and a tool is used to hook and pull the vein out through the incision.
In view of this background, the need remains for improved and alternative techniques, devices and systems for affecting the venous system to treat venous conditions. The present invention is addressed to these needs.